Drying



P. A. SHAW Aug. 19, 1952 DRYING Filed. Oct. 15, 1948 2 SHEETS-SHEET lFURNACE 20 CL EANOUT 4O DAMPER CONTROLLED INLET 24 COOKED FISH MEAL FROMPRESS 7O COARSE PARTICLES FUNNEL -SHAPED DRYING CHAMBER STAR FEEDER 74'DIS IN TE GRA TOR 7/ PREHEA TED F/SHMEAL 8 GAS TO DRYER emu/v0 LEVELFIG. 3.

VERTICAL VANES INVEN TOR. PAUL A. SHAW TELESCOPE PIPE FURNACE CHE CKERWORK WALL AT TORNEY Aug. 19, 1952 s w 1 2,607,537

DRYING Filed 0012- 15, 1948 SHEETS-SHEET 2 C ONNE C T/ON 70 CENTRALSUCT/ON PIPE 60;

' INVENTOR. PAUL A. SHAW AT TORNEV Patented Aug. 19, 1952 UNITED STATESPATENT OFFICE},

DRYIN G Paul A. Shaw, Wilmington, Calif., assignor to Terminal IslandSea Foods, Ltd., Terminal Island, Calif., a corporation of CaliforniaApplication October 15, 1948; SerialNo. 54,616

13 Claims. 1 ilns invention relates to drying, and particularly to thedrying of heterogeneous finely divided material of low average bulkdensity and which tends to deteriorate at high temperature. However, theapparatus of the invention may be employed advantageously in thetreatment of a variety of materials, including those which arehomogeneous and those which can be subjected to high temperaturewithoutdamage.

This application is a continuation-in-part of my co-pending applicationSerial No. 735,511 filed March 18, 1947, now Patent No. 2,513,370.

It is common practice to dry solids by suspending them in a current ofdrying gas, say hot air, and many products are dried, successfully inthis fashion at the present time, although thermal efllciencies are notalways as high'as might be desired. In otherinstances, such dryingprocedures are not satisfactory, since they result in a scorching of thematerial being dried -or some other deterioration in quality.

Design of, structures in which low density 2. That large particles arenot only heavier.

than small particles but also require a. longer time to dry;

That for any properly dried product, the particles are of uniformspecific gravity.

There may be cases in which these assumptions are true, but in the caseof fish meal and other materials, they are incorrect and equipmentdesigned in accordance with themdoes not operate properly. Wet fish mealis a heterogeneous mixture of bone, muscle, scale, skin and gutparticles. Particles vary with respect to size, shape, moisture content,texture and density. There is a great difference between round, densetuna eyes and fiat, light bones, and between flufiy muscle tissue anddense leathery gut tissue. Even though the meal has been cooked, pressedand passed through a disintegrating mill, its constituents do not losetheir identity and'variations such as those noted above continue toexist. Both Dlant experience and laboratory tests show that many undriedparticles of fish meal are lighter and more buoyant in air than othercompletely dried particles.

stream. Processes or apparatus which classify So. although each in-.dividual particle of fish meal tends to lighten on- "2 materialparticles on the basis of density either in the drying .gas current, orsubsequently in an operationfrom which the more dense particlesv arereturned for additional drying, are not optipractical andefiicient meansfor low temperature drying of fish meal or the like while it issuspended in a gas current, say .warm air. The scorching of protein, theodor nuisance, the smo production, the vitamin loss and the loweredfeeding value which occur in the drying of fish meal in conventionaldryers (including not only the' air current types but also direct firedor steam tube rotary driers) are avoided in the practice of the.invention. Moreover, the apparatus of the invention is compact, and hasextremely high throughput in terms of space occupied. In it the buoyancyand the carrying power of the stream of drying gas are maintained whilean adequate lag between particle speed and gas speed is induced topermit proper drying in relatively small space.

The apparatus of the invention in its simplest form comprises a towerhaving a chamber, the

cross section of which increases with height. An

inverted frusto-com'cal chamber is preferred, but one of invertedfrusto-pyramidal shape may also be employed. A conduit, preferablydisposed vertically, opens into the small bottom portion of the chamber.A current of drying gas is forced up through the conduit and thechamber, either by pressure, from below or suction from above. Thematerial to be'dried. say fish meal or peat moss, is introduced into theconduit and carried upward into the funnel-shaped chamber by the ascurrent, where it fountains outward with the increasing cross sectionand decreased velocity, thereby partially losing its buoyancy. The inletsection velocity and cone dimensions are so arranged that a portion ofboth the heavy and light ,solid particles will be carried to the full.

cone height with considerable remaining velocity. At a relatively highpoint, say near the top of the flared chamber, a swirling motion isimparted to the gas stream by-means of a stationary bafile having radialvanesv which may be .made adjustablewith respect to the angle which theymake with the horizontal. Solid particles-within the gas stream'tend toresist this sudden change of gas direction, strike the baflle and aredeflected downward to be again buoyed up by higher velocitiesin thelower cone area. Some particles, both heavy and'light, will, of course,remain in the gas stream and be c'arriedupward in a spiral motion.

matter passing through, the oblique baffles is equal to that'being fed.Once having passed the bafile, the spiral motion will continue to carrythe heavy and light, large and small, particles :lower portion of analternative form of dryer of upward and-out, say through a fan to acyclone separator.

The angle of the bafile adjustment together" with the total air volumedetermines theequ'i librium load and therefore the drying time;

Oddly enough, the holding time is reduced byv moving the bafiies towarda horizontal position,

i. e. the holding time of material in the dryeris 4 greater when thebaffles are set at 35 from the horizontal than. when they areset at10.9...from the horizontal. :This is due..to-.increas'ed gas.

velocity at the lower angle which permits a higher percentage ofentrainedsolid particles to continue upward with the gas ratherithanbeing deflected downward'. The .total gasvolumeand bafile angle :maytherefore; be. .adjustedso as to establish optimum..conditions for theparticular...

material beingdried. .1

- If desired, the=apparatus. may'.have .a plurality.

of radiallyvaned baffles superposed one above the other, the vanes.ofsuccessive bafiles. maybe them; if a plurality. isemployed, may be.adjusted to suit the particular materiaLto be. dried.

It -is'de'sirable to-avoid. turbulence-an swirling in the funnel-shapedchamber exceptgimmediately below A the .first or lowest: bafiie, .since'it has been determinedexperimentally that an abrupt-change of gasdirection and asudden: beginning: of swirl ing-action is desirable. 1With this in mind, I-pre fer:-to.;provide platesin thelower conduit,or-in the funnel-eshaped chamber or both to direct the gas upward andtop-revent turbulence or swirling in the conduit and i'nsth'elower-portion ofthe-funnel-shaped chamber. i

lit-order to facilitatethe -swirling induced by the radially vanedbar-lies. in the upper-portionof the d ryer, I prefer to withdraw thegas from-thespacezabovethe baffles: through a tangential pipe.

In the preferred design, the tangential pipe is connected to sucti'on fan, -which exhausts to a cyclone collector orthe like in which the'bulkof the driedproduct is collected. 1 1 1 Another.extremely desirablefeature which may beincorporatedin the dryer of the invention isapipewhich is connected-seine dryer outlet, for

examplain or just ahead of the suction fan and drops 'down throughf theconduit'below the funnel-shapedahamber. Friction of gas against theinlet conduit walls creates a lowered velocity-adjacent to-the shell andvsomeparticles. principally I the heaviest ones, which have beendeflected downward to the cone wall will continue down- Ward close totheshellxand collect in theibo'ttom hopper. The small: diameter pipewith considerably ghigher gas velocities; serves to re-zentrain'these-particles, now drypand transportthem to thefan; Withsomeprcductsit isdesirable to end.

4 this pipe above or below the'adjustable cone bafile rather than at thefan inlet.

The foregoing and other aspects of the invention are explained in detailwith reference to the accompanying drawings in which:

Fig. 1 is a diagrammatic vertical elevation, partly in section, of adrying plant designed in accordance with the inventionp'articularly forthe drying'of fish meal;

Fig. 2 is a plan view of the apparatus of Fig 1;

Fig. 3 is a fragmentary vertical section of the the invention;

Fig. 4 is an elevation of the vertical conduit at the bottom of thedryer of Figs. 1 and 2;

Fig. 5 is a plan View of the conduit of Fig, 4 showing the arrangementof the interior plates provided to streamline the gas and preventturbulence; Y

Fig. 6 is a vertical elevation of the funnelshaped drying. chamber ofthe apparatusof Figs.

1 and2;

Fig. "7 is a' planview of thedrying chamber of Fig 6 showing thearrangement of a spider ofplates providedto prevent turbulence of gas inthecharnber until thevaned baille at the top of the chamber is reached;

Fig. 8 is an elevationoi'a cylindrical chamber in the apparatus of Figs.1 and 2 above the funnelshaped chamber and containing the'first of twotransverse baffies withradial vanes;

Fig. 9 is aplan view of the chamber of Fig.8 showing details of thetransverse baflie referred to in connectionwithFig. 8;

Fig. i 10 is an elevation ofsa: cylindrical chamber bulk density andhigh'moisture content, such asv sewage-sludge, peat moss, etc. Heat fortheoperation is suppli'ed 'by a conventional furnace orfire box 20.furnace pass .into'an exit fiue 22 which rises-vertically and then dropsdown toa communicating hopperi23;. Colda'irin controlled amount isintroducedfinto the bottom of the flue through a dampei controlled inlet25. I 1

Thejd-ryer proper isdisposedabove the hopper.

lthagx-a lower vertical cylindrical pipe section 25which'opens into a.verticalupwardly flaring frustot-conical chamber 2B; this funnel-shapedchamber-opens into an upright cylindrical chamber -zl 'd isposeddirectly above it and having thesainediameter asthe upper portion'ofthecone. -A horizontal pipe 2 8 projects tangentially from the upperportion of thecylinderand serves'as a connection betweeen the. cylinderand the suction side of a powerdriven fan'29, the outlet i-lil-of whichis connected touaconventional cyclone-"collector 3| In many"instancesithe chamber 27 -rnay-only be of sufiicient: height above thecone to providefor the tangent outlet-28, since practically all dryingoccurs-below the cone bafile- Vertical vanes32 in-thefo-rm of a grid aredis posed inlth'e lowe'r or inlet pipe 25" of the dryer. The :materialto be-dried', say fish-meal, 'is fed The hot gases of combustionfromthe" The upper end of continuously intothe pipe 25 bya screwfeeder 33disposed just abovethese vanes. In the frusto-conical'; or funnel-shapedcham-.

ber of the dryer there is another set of vertical vanes 34 arranged tostreamline the gas anisolid flow through the lower portion of thischamber so as to present a vertically rising stream abrupt 1y to theaction of. a first transverse, bafileifi (see Figs. 8 and 9) disposed ator slightly above thelevel wherethe funnelrsha'ped chamberv joins theupper cylindrical chamber. A second bafile 31 (see Figs. and'lD'haVingradial-vanes is disposed in the upper cylindrical chamber abouttwo-.thirdsof: the way .up, Sor, just below the tangential outletpipe-.---=If"the upper chamber is short the second baffle- .31 may bedispensedwith.

.A concentric vertical pipe 38 of relatively small diameter extends froma point near the bottom of the hopper upward throughthe' various.superimposed sections of the dryer and is connected at itsupper end tothe suction pipe 28 which forms theinlettothefan; v u- The flue andhopper construction shownin Figs. 1 and 2 is: preferred for a number ofreasons. The cold air entering the flu'euat itsbot tom. adjacent thefurnace'protects thewall 39 between the two portions of the fine, fromthe directaction of the hot gases, and-thej-sharp bendat the top of theflue. assures proper, mixing ofthe furnace gases and the cold air whichis drawn in through the dampers. Consequently,- the surfaces in thehopper etc. which, may come incontact with the material to be dried donot become hot enough to cause scorchingofmate- 'rial which may come incontact with .or-itlodge upon them. Second, the flue and hopperstructure is such that it can all be builtabove ground level, permittingeasy access to the bottom of the hopper for cleaning, etc. The bottom ofthe hopperv is provided with a cleanout door 40 which is openedperiodicallyto permit tramp iron and other very heavy material presentin the feed to be withdrawn into a wheelbarrow, car, or the like (notshown). If desired, an opening of relatively small crosssectiori maybeprovided in the hopper bottom for continuous discharge of heavymaterial. v I

, The'vertical vanes in the lower pipesection of the dryer of Figs. 1and 2 arebest seenin'Fig's. 4 and 5L The vanes comprise radial plates 4!ex tendingffrom the interior suction pipe to the outside wall of thecylinder, and held together by concentric ring plates 42, thearrangement being such that a number of openings 43 of roughly equalcross section are provided. The 'eifect of the, vanes, which are,located in the bottom of the 'pipewith their major surfaces vertical, isto reduce turbulence caused by the change'ofgas direction etc. in theflue and hopper. t

The vertical vanes 34 .in the funnel-shaped chamber of the dryer arebest seen in Fig'sifi and 7. They are simply radial plates 44 whichextend'from the central pipe to the wallet the cone withtheir loweredges about half-'wayup the cone. They can be constructed as aninte'gral"splder unit and simply set into the cone; Their function is to keepthestream of gas and suspended solids rising vertically, withoutsubstantial swirling, until the first transverse baflle is reached. I

This transverse baffle' 36 is shown indetail in Figs. 8 and9. Itcomprises eight segments 45, each of which is rotatable on a radial axisextendingfrom a'hub46 out throughthe shell of the dryer. A nut 41 on theoutside-is threaded to this. shaft parallel'to the'majjOr-surface of thevane- It serv storotat th van and to. nd ea the; an e ;it mak -w th t e.ho nta1 -Whe all the vanes are horizontal, they substantially l se.the. dryer. cross s c n; but in ope ation they aresetas:;louvres at japproximately equal angles. The anglewith thehorizontal may range. from-10...-to*a1m t 90.."- ..*'.1he ave ag tim hat material is, heldin thedryer :is adjusted by;, adlusting. the angle f t e radia ba l s-axe notd above, the holding timei reduced ;by;m0v, 1. the baffles toward ahorizontal position,. i. e. the holding time of material in the dryer isgreater when the baflies are. set at 35.from the horiaontalthan whenthey are set at 10 f rom the horizontal.

The upper transverse jbaflie.; 3'|;isbest seenin Figs..10 and 11. .,-Ithas-sixeradial. vanes 50 gacupying .about{ three; quarters-of the crosssection. Thev other-quarter isclosed by, a floor plate 5| whichunderlies the tangentialofitake pipe; 2-3. Crdinarily, the vanes neednet be adjustable and are .simply bent pieshaped plates fastened; at

onev edge to radial spokes 52;.Which extendfrom a central hub to theshell of the dryer. In some cases,.the 1upp er transverse-baflie maybeeliminated. I Inthose casesin which i1) is employed its vanes vmaybesoset, that it tends toreverse the direction of swirling imparted by thelowertranse verse baffle, or vice versa, .As shown in,Figs -10 and 11,the .structurepreferably. isysuch that if the gas stream swirlscounter-clockwise. as'a re;- sult of passage throughthe lower baflie itshould be. made 20 swirl counter-clockwise through the up ri ey f Thecone angle is not criticaLbut generally speaking, the heavier is thematerialto bedried the steeper the cone. wa ls. should be. For fishmeal,v the wallangle shown in Figs. 1 and 6 is aboutloptimum. f I. p gA. dryerllike that just described and of relatively large size has beenoperatedcontinuously to remove moisture frdrhffishmeal. It has a totalheight of about 2 5 feet and the funnel-shaped portionof the dryer is- 7feet high and '6 feet; vin diameter atthe top. The; fan is driven by'alO motor.

. .'Ihe temperature of thejgases entering the bot} tom of, the dryer islow, ranging from. 200 .to

300 F. The fish meal is heated to a. maximum temperature ranging from tol25 F. ;At these low temperatures the meal does not scorch or give offobjectionable odors or fumes.

Tuna, mackerel and'sardine meal'have been dried in the equipment withexcellent results from the standpointof character ofproduct andthermalefliciency; -In all cases the dried meal is light and flufiyandof -much lighter colorthan that produced in conventional dr ers.Moreover,

the dried meal has a higher feedingvalue than volumeof airupwardlythrough the mass of meal in. the binu This allows oxidation of fatzinvthe meal to be substantially completed prior to pack.-

aging-so that the heat'otoxidauon-isnotavaiiable'='to. injure theproductdo rfg s't ag "Inoperating the-drier 6f desirable to"- have a '2 -pentemperature recorder and eontrol-ler,=one tor recording-the:inlet-ternof the mixd -ai'r arrd': furnace 'ga's'-, the pen recording-andcontrolling; the-"finish temperature by aibulb placed i-n 'th: equipment,be'ytan'dLthe drsomecon {Suitable-gauges to indioate'suetion, -i-.-e.at the ho per-am fan intake are recommended,together with eitheravariable speed drive-onthesenor-editable.iouvres toxaon-z trel the'total air1 yolume:

emperadoaor the dryer of Fi'gs. 21 and 2 is Hows: I g a 'ewarmeaseonnsting ore mixture -o'f rcom hustien'gases 'fromthe furnaee andthe bled-4n air meets the introduced feed and tends-*to icarry inventionit is the wet'particlesthereof up into the -tunnel for cone or thedryer. iilust belowth'eiirst trans= and s'uspended 'sol-ids su'fiers anabruptvchange of direction; Many of'the particle's strikeitheibatfieand-are bounceafimownward intoithe -lower:por-

tion "of the cone whe're veloci'tie's are higher: and

The central pipe-is conneeted directl-y to the fan by connector- "(seeEigs. 10 flrfd 11'). A high suctione ii's'tsattirelower en'd df the'pipesuilie'ienti-to'entrain' the heavy particles ander-aw them -swordthrough the central pipe theran, where they 'j oin "the particles drawnup through the outerportionof the drier; 1 ram-p iron and other ==impurities-=-which are tO'o heavy to be 'l iftefby --even the high"si'iiitiirl of, the center pipe collect in the bottomor the "thepreheating a-idsdisintegration "and yields a iiuffier final product.

'In' the-apparatus of Fig. 3 'hot 'fu'rnace gase's' pa'ss' 'through achecker wors -wan; "veneereer the furna'ee into a 'down draft flue 15cold' air to dil-iite thefurnace 'gasesl being dramin through 'a-"iia mpered openin 5-5 the Rio-D 6f -the::flue.

'rhe lower'e'nd of the hue opens into-a pwis into iyh-ieh thecemm-rpipesor the drying QOIUm II- pTOf jects. This pipehas-=a-telescoped end section- 17 Whih sl-ides "overthe rester the pipeand-may be set 1 at various levels; so as to adjust the degree orsuctior'rat'th bottom or the pit. -'etc;,=Which is-too*heaVyto be suekeaup hpit, whieh is clea n'ed' out-perioeieauy;:sayettimes Ofi'ShiIbi Fdown-:-

The rest for: the apparatus'iofil iggiiris :sulostem-v .iOrdinarily'the' fish' mealifromrthe. cyclone :collector is subjected to grindingprior to sacking. Increased thermal :efiic-ienbyiforcthefish :meal.dnying operation :may .bgabbtained byv-ericlosing the igrin'der ;(n'ot=shown and "passing the-warm exhaust vgases zfrom tthe cyclonerexhaust'through themgrinder inclosurerandzthenee'to i-a smaller?invention. Thus the central pipeWhichis em-' ployed todraw I up theheaviest particles by means or higher suctiom m'ay be disposedoutside-the-shell of the-drying tower. This however; complicates thedesi'gh-and: is ordinarily not to be desired. V J :Ahumb'ermf the dryerunits maybe connected either -inseri'es'or in parallelw V .To'summarize, .the dryer of the V invention is particularly useful in drying' finely dividedma terials of low bulk density, and is particularlyuseful in :drying heterogeneous mater-ial such-as fish meal, which:includes 'vparticle's of widely difierent' density. It permits dryingat very low temperatures, below those at which many conventional dryersare operative. The low dryer temperature reduces fire hazards,eliminates scorching. of combustible products and in fthe case of :fishmeaLz etc ;produces animprove'd product, i lighter. Land imor'e uniform:in color, miner; and with a -higher'snutritional values It canbeloperated'io'n 'fish m'eal etc, without calls ingiodo'r' nuisancei'orsmog serious probleins' in congested industrial areas Iaa'st1y,=-With-'-'cert'ain materials: 'i. e. peatlimos's; with .-a rr noi's'tu're content. of moisturegmay -b elimin ated tube having-substantially para-llmechanically (as mist) toe-large extenh so that the evaporation"efficiency in (if-thermal input may be very}high'+""insome I cases i-nexcess c ela vm v IJ'II']. a. di-ie'r, the oombiiiatioh-whih com prises-an upwardly flaringedrying --cha-mber,a "e1 walls disposed in asu-bstari't'is'ailly upri gl-it positionand' opening fm-to the bottom ofthe flared 'chamber, means for feeding material' to be dried int-,0 thetub ei means for passing acurrent *of drying gas upwardly through thetube'and the ehamber'with' stiffieient force to buoy u-pia'tleast*someofthe material to be "dried, means ion-preventing turbulentflow of thedrying gas in the tube and the. lowerpbr tion of "the flared "chamber;and "a j 'bafiie for abruptly'imparting aswirlingmotion'tdthe gas andthe "material fbuoyedup'Tby it, "said bafll beingdisposed:in'thedrierat'a level'near the'to'p of thefiaredthamberandtrans'verse "to theup ward passage"of'thelfgas. v r "2. "In adrier;th'e combination which comprises an upwardly flaring "drying ehi'hbei', :a tube having substantially;parallel wan-5' .-disposedfih asubstantially upright position and openingjint'o the bottom "of thefiaredf'chli'fibr, meansi'for feeding materialto' be -dried into thetube, means "for passing a current or 'dryingjg'as upwardly through "thetube and -.the .c-hambr -tililih?'slii'iicient'ffoi ce .to buoy-up,atlleast 'so'me'of the materialto bedried, means comprising'vanesfdisposed iwith- .thei-r major surfaces. Ilying Iinf'th'd-ireetiongof gas now.- in Jth' Itube i'for preventing turbulentflowoflthefldrying gasihth tubeand the lower portion-of- {the -fia;redchamber, and a bafile'for abruptly imparting a swirling-motion to thegas and the material buoyed up by ,it, said-bafile beingdisposed-in thedrierat ai-le vel near--the-; top of the :fia-red chamber and transverse-to the upward, passia e ottheigas.

3. In a i'r-rdrier, z-the: combination which com prises wan -"upWardlysharing L'drying chamber, :ia

tube having substantially parallel walls disposed in a substantiallyupright position and opening into the bottom vof the flared chamber,means for feeding material to be dried into the tube, means for passinga..cur rent of drying gas upwardly through the tube and the chamber withsufllcient force to buoy up at least. some of the material to be dried,means comprising radial vanes with substantially upright major surfacesdisposed in the flared chamber for preventing turbulent flow of thedrying gas in the lower'portion of the flared chamber, and a vmultivaned baflie for abruptly imparting a swirling motion to the gasand the material buoyed up by it, said. baiile being disposed in thedrier at a level'nea'rfl the top of the fflared chamber and transversetothe upwardpassage of the gas. I

4. In a drier, the combination which'fcomprises an upwardly flaringdrying chambena tube having substantially parallel walls disposed in asubstantially upright position and opening into the flared chamber,means for feedinggnaterial'to be dried into the tube, means for passinga current of drying gas upwardly through the tube and'the chamber withsuificient force 'to buoy up at least some of rthe material to'be dried,means for preventing turbulentflow of the drying gas in the tube, meansfor preventing turbulent flow of the drying gas in the lower portion ofthe flared chamber, and a baflie comprising radial plates disposed on aslant from the horizontal for abruptly imparting a swirling motion tothe gas and the material buoyed up by it, said baffle being disposed inthe path of the gas and transverse thereto at a level near the top ofthe flared chamber.

5. Apparatus according to claim 4 provided with means for adjusting theslant of the radial plates.

6. In a drier, the combination which comprises an upwardly flaringdrying chamber, a tube having substantially parallel walls disposed in asubstantially upright position and opening into the bottom of the flaredchamber, means for feeding material to be dried into the tube, means forpassing a current of drying gas upwardly through the tube and thechamber with suflicient force to I buoy up at least some of the materialto bedried,

a level near the top of the flared chamber above the upright plates.

7. In a drier, the combination which comprises an upwardly flaringdrying chamber, a tube having substantially parallel walls disposed in asubstantially upright position and opening into the bottom of the flaredchamber, the horizontal cross section of the tube being substantiallythe same as the horizontal cross section of the flared chamber at thelevel at which the tube opens into it, means for feeding material to bedried into the tube, means for passing a current of drying gas upwardlythrough the tube and the chamber with sufficient force to buoy up atleast some of the material to be dried, means for preventing turbulentflow of the drying gas in the tube and the lower portion of the flaredchamber, a first bafiie for abruptly imparting a swirling motion to thegas and, the material buoyed up by it disposed at a level near the topof the flared chamber'and transverse to the direction of gas passage,and asecond baflie to impart swirling disposedin the drier a; ove thefirst and transverse to'the'direction-of'gas passage. v

8. In a drier,*the combination 'which'comprises anjupwardly flaringdrying chamber, a tube having substantially parallel walls disposed in asubstantially upright'pos'it'ion and opening into the flared chamber,means for feeding'material to be dried into-the tube, meansfor passing acurrent of1drying gas upwardly through the tube and the chamber withsufficient .forceto buoy up at" least some of the1inaterial totbe dried,means for preventing turbulent flow of the drying gas'in' the .tube' andthe lower portion of the flared chamber, and two superposed transversebaffles for abruptly imparting aswirling. motion to the gas'and thematerial buoyed up by it at a level near lthe'top of' theflared'tchamber, the lower of thetwoxbaffiesibeingnear'the top of theflared chamber and having radialjplates rotatable to a slant with thehorizontal, andrmeans for adj-ustingrthe'slant of the plates.- 9. Ina-drier, thecombination whichcomprises an upwardlyrfla'ring dryingchamber, a tube hav ing substantially parallel walls disposed in a substantiallyzuprightposition and opening into the bottom of the flaredchamber, means for feeding material to be dried into the tube, means forsucking a current of drying gas upwardly through the tube and thechamber with sufficient force to buoy up at least some of the materialto be dried, means for preventing turbulent flow of the drying gas inthe tube and the lower portion of the flared chamber, and a baffle forabruptly imparting a swirling motion to the gas and the material buoyedup by it disposed in the drier at a level near the top of the flaredchamber and transverse to the direction of gas passage, a hopper belowthe tube and communicating therewith,

a pipe opening into the hopper, and means for applying a higher degreeof suction to the pipe than to the tube and flared chamber.

10. Apparatus according to claim 9 in which the pipe is disposed uprightand passes through the tube and the drying chamber.

11. In a drier, the combination which comprises an upwardly flaringdrying chamber, a tube having substantially parallel walls disposed in asubstantially upright position and opening into the bottom of the flaredchamber, means for feeding material to be dried into the tube, means forpassing a current of drying gas upwardly through the tube and thechamber with suflicient' force to buoy up at least some of the materialto be dried, means for preventing turbulent flow of the drying gas inthe tube and the lower portion of the flared chamber, a bafiie forabruptly imparting a swirling motion to the gas and the material buoyedup by it disposed in the drier at a level near the top of the flaredchamber and transverse to the direction of gas passage, a hopper belowthe tube and communicating therewith, a flue passing upward and openinginto the top of the hopper, means for introducing hot gas into the sideof the flue remote from the hopper, and means for introducing cooler gasinto the flue below the point at which the hot gas is introduced.

12. In a drier, the combination which comprises an upwardly flaringdrying chamber, a tube having substantially parallel walls disposed in asubstantially upright position and opening into the bottom of. the.flared chamber, means ;-for feeding? material to: bedried-together'withwarm gaseinto the tube, means i011 passing. a;current of ;drying: gas .upwardlythrough the-tube zandethe chamber with'suflicient force to rbuoy :up at.-1ea st some of the materialtQ'bQtdIid, means'fonpreventi-ngturbulentflowof the dryinggas. in thetube and the lower-portion of the flared-chamber, axbaffie for abruptlyimparting 'a swirling;:motion to" the; gas anq the; material buoyed. upby, it' dis poseclinthe i clrier at a level near'the" top of; thefiarecl chamber ancttransvers'e-to the direction of gaspassage;a'fiisintegratoriforthen'iaterial tbibedried.connectedftortlieifeeltmeansiarrd'a conduit for: passing'zwarmsgas into a he :disintegrator: from theztube 7' a 1' .'1.3.=;In=: adryer. the" combination: which com; prises atube havingnsubstantiallyparallel walls disposed'iinc a; substantially upright position; anupwardly flaring'gdrying :chamberdisposed above theetube withitsbottomin rcommunicationzthere withgsmeans forfeeding material to'bedri'ediinto the-tube; vmeans for" passing a .current of; dryinggasupwardly through the? tube and the chamber with sufiicient force" to:*buoy up a' large partiof the; materialto bezdried; means for preventingturbulentrfiowof'the drying: gasi-in' the-tube :and the'lower portionoflthe flared-chamber, atransverse' bafile for" abruptly impartingaswirling s am-s37 12 motion .toqthe. gas-and the material buoyedl up byittdis'posed' at alevel near. the top of the-flared chamber,avchamherrcdisposed. above the flared chamber, and anroutlet conduit.tangential, to said,,upper,chamber'.

- PAUL A. SHAW.

v f REFERENCESCITED. The -following references are of: record: in [thefilee-ofzthis-ipatent: i W "UNITED STATESPA I'ENTS iDateQ Shaw July.4;"1950

